1. Field of the Invention
The present invention relates to a tilt adjusting-type steering apparatus which is provided with a tilt adjusting mechanism for adjusting the height of a steering wheel in a car or other vehicles in accordance with the physical dimensions of the driver.
2. Related Background Art
As a steering apparatus to be mounted on a car or other vehicles, there is conventionally known a tilt adjusting-type steering apparatus in which the height of the steering wheel can be adjusted in accordance with the physical dimensions of the driver. The adjustment of the height of the steering wheel in this tilt adjusting-type steering apparatus is generally performed by releasing a lock so that an upper column member can be move to change its inclination with respect to a lower column member, so as to thereby set the height of the steering wheel to a desired position value, and then locking the upper column member with respect to the lower column member. A mechanism for locking the upper column member and releasing this lock in this case is a tilt lock mechanism.
An example of the tilt lock mechanism is disclosed in Japanese Utility Model Publication No. 2-34145, which is illustrated in FIGS. 30 and 31.
In the tilt adjusting-type steering apparatus shown in these drawings, a lower column 52 for supporting a lower steering shaft 51 to be rotatable is fixed to the car body (not shown) through a bracket 53. An upper column 55 for supporting an upper steering shaft 54 to be rotatable is supported by the bracket 53 to allow free tilting movement with tilt shafts 56, 57 as the center thereof. A steering wheel (not shown) is attached to the upper steering shaft 54. A gear portion 58 fixed on the side of the upper column 55 is caused to mesh with a movable gear member 59 which is supported to freely oscillate by the bracket 53, and the movable gear member 59 is pressed from the back thereof by the tilt lock mechanism to effect locking. The tilt lock mechanism comprises right and left support hangers 60, 61 with their upper ends respectively supported to freely oscillate by the tilt pivots or shafts 56, 57, a roller support shaft 62 fixed to the lower ends of these support hangers 60, 61, and a roller 63 supported to freely rotate by the roller support shaft 62. The roller support shaft 62 is formed with a tilt lever 64 as a unitary structure and arranged so that the roller 63 can be moved in a right and left direction (in FIG. 30) by operating the tilt lever 64.
The movable gear member 59 is locked and is released from the lock by means of the tilt lock mechanism having the above-mentioned structure in the following manner. When the tilt lever 64 in its locked state in FIG. 30 is rotated in a counter-clockwise direction in the same drawing against a biasing force of a spring 65, the roller 63 is moved to the right about the tilt pivots 56, 57 to be retracted from a taper portion 66 of the movable gear member 59, whereby the movable gear member 59 is released from the fixed gear 58. In this released state, the upper column 55 is moved to change its inclination with respect to the bracket 53 so as to set the steering wheel at a proper position. After that, when the tilt lever 64 is released, the roller 63 is moved to the left by the biasing force of the spring 65 so as to press the taper portion 66, whereby the movable gear member 59 is meshed with the fixed gear 58 to be locked. Upon this locking, the adjustment of the height of the steering wheel is completed.
In the above-mentioned tilt adjusting-type steering apparatus, the roller 63 of the tilt lock mechanism is protruded downward, so the roller 63 is positioned around the knees of the driver. As a result, there is a risk that the driver's knees may be hit by the roller 63 during driving, or that the lock of the movable gear member 59 may be released.
In order to prevent such accident, it is possible to cover the roller 63 with a lid or cover. However, with this arrangement, the number of constituent parts is increased so as to further narrow a space around the knees of the driver disadvantageously.